Small molecule modulators of biomacromolecule function, in particular, receptors and enzymes, are widely used both as drugs to treat human diseases and as tool compounds to study biological processes. Importantly, small molecules enable scientific approaches that offer high spatial and temporal resolution, which can rarely be achieved with traditional molecular biological methods. However, when used in the context of larger biological settings such as organs or whole organisms, the spatiotemporal resolution of small molecules is limited and may be insufficient, resulting in side effects (when used as a drug) and indefinite experimental outcomes (when used as a tool). Thus, approaches that will provide an additional level of control with respect to time and space are highly desirable.